In the coming year the nervous system specific cell surface glycoprotein, band 1 will be purified to homogeneity from mouse brain and monospecific antisera to it produced. The species and cell type distribution of band 1 will be examined. The binding of band 1 to muscle, neuronal, glial, and non-neural cultured cells will be carefully examined. These studies will require controlled proteolysis of band 1 to obtain a water soluble molecule from the detergent soluble form. The possibilities that band 1 is a mitogen or tropic factor for muscle cells will also be tested. Efforts to identify nervous system specific cell surface components in addition to band 1 will continue. Several approaches will be used to reduce the high level of apparently non-specific binding of certain N18 proteins. Cultures of primary muscle which may have a greater number of "receptor" sites will be tested with exfoliated N18 neuroblastoma proteins. The exfoliated proteins will be fractionated with lectin affinity columns in efforts to remove these components which bind to all cells.